Hrafn Loftsson


2020

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Effectively Aligning and Filtering Parallel Corpora under Sparse Data Conditions
Steinþór Steingrímsson | Hrafn Loftsson | Andy Way
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics: Student Research Workshop

Parallel corpora are key to developing good machine translation systems. However, abundant parallel data are hard to come by, especially for languages with a low number of speakers. When rich morphology exacerbates the data sparsity problem, it is imperative to have accurate alignment and filtering methods that can help make the most of what is available by maximising the number of correctly translated segments in a corpus and minimising noise by removing incorrect translations and segments containing extraneous data. This paper sets out a research plan for improving alignment and filtering methods for parallel texts in low-resource settings. We propose an effective unsupervised alignment method to tackle the alignment problem. Moreover, we propose a strategy to supplement state-of-the-art models with automatically extracted information using basic NLP tools to effectively handle rich morphology.

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Language Technology Programme for Icelandic 2019-2023
Anna Nikulásdóttir | Jón Guðnason | Anton Karl Ingason | Hrafn Loftsson | Eiríkur Rögnvaldsson | Einar Freyr Sigurðsson | Steinþór Steingrímsson
Proceedings of The 12th Language Resources and Evaluation Conference

In this paper, we describe a new national language technology programme for Icelandic. The programme, which spans a period of five years, aims at making Icelandic usable in communication and interactions in the digital world, by developing accessible, open-source language resources and software. The research and development work within the programme is carried out by a consortium of universities, institutions, and private companies, with a strong emphasis on cooperation between academia and industries. Five core projects will be the main content of the programme: language resources, speech recognition, speech synthesis, machine translation, and spell and grammar checking. We also describe other national language technology programmes and give an overview over the history of language technology in Iceland.

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Kvistur 2.0: a BiLSTM Compound Splitter for Icelandic
Jón Daðason | David Mollberg | Hrafn Loftsson | Kristín Bjarnadóttir
Proceedings of The 12th Language Resources and Evaluation Conference

In this paper, we present a character-based BiLSTM model for splitting Icelandic compound words, and show how varying amounts of training data affects the performance of the model. Compounding is highly productive in Icelandic, and new compounds are constantly being created. This results in a large number of out-of-vocabulary (OOV) words, negatively impacting the performance of many NLP tools. Our model is trained on a dataset of 2.9 million unique word forms and their constituent structures from the Database of Icelandic Morphology. The model learns how to split compound words into two parts and can be used to derive the constituent structure of any word form. Knowing the constituent structure of a word form makes it possible to generate the optimal split for a given task, e.g., a full split for subword tokenization, or, in the case of part-of-speech tagging, splitting an OOV word until the largest known morphological head is found. The model outperforms other previously published methods when evaluated on a corpus of manually split word forms. This method has been integrated into Kvistur, an Icelandic compound word analyzer.